Yosemite National Park was established on 01 October 1890, and is the Nation's third oldest national park. Yosemite National Park is a showcase of spectacular geological features, including the greatest concentration of granite domes in the world and the largest exposed granite monolith in the world.
Yosemite National Park is a showcase of spectacular geological features, including the greatest concentration of granite domes in the world and the largest exposed granite monolith in the world.

Most people think of Yosemite Valley with granite monoliths like Half Dome and numerous waterfalls.
The valley is surrounded by Yosemite National Park, a 1,200 square mile park containing deep valleys, grand meadows, ancient giant sequoias, a vast wilderness area, and much more.

It is the sixth most visited National Park with 4 million visitors a year.

Geology:
400-365 Million years ago (MYA) magma which cooled underground (Igneous rock) formed the granite.
155-300 MYA the North American continental plate drifted away from the super-continent of Pangea and moved westward. It collided with a Pacific Island chain in an area which is now the Sierra Nevada.
163-143 MYA compression caused uplifting of the Sierra Nevada to about 3/4 of present height.
As the mountains rose, the land tilted and the westward flowing Merced River accelerated, carving deep, v-shaped river canyons. Later, massive glaciers flowed down the canyons.
2 million to 20,000 yrs. ago colder temperatures slowed melting and eventually glaciers formed and began to carve away at the v-shaped canyons, transforming them into u-shaped valleys. Tributary streams did not carve their canyons as deep as Merced Canyon. Glaciers sheared off these canyons leaving them as "hanging valleys." Tributary creeks, which had once joined the main stream at the same elevation, now plummeted off of shear cliffs, giving birth to the park's famed waterfalls. Eventually, sediment washed down out of the high country, filled in Lake Yosemite to form the present valley floor.

All year, though by mid to late summer, it narrows and separates into one, two, or three falls as water flows decrease;

late May

Illilouette Fall

370 ft

all year. Widest falls.

late May

* Dates are approximate. It depends on the weather, the amount of snow and when snow melt starts.

Horsetail Fall is famous for appearing to be on fire when it reflects the orange glow of sunset in mid- to late-February. It falls off of the east side of El Capitan and is best seen from just east of El Capitan.